"Sleep" takes a refreshing approach to horror by interweaving the bizarre sleepwalking story of a newlywed couple with a romance and mystery thriller, telling a nuanced tale of marriage and family.

Jason Yu's debut feature film is a unique fusion of genres as it evokes an unsettling sense of supernatural phenomena through the couple transitioning to parenthood.

The three-part story follows a newly married couple, Hyun-su (Lee Sun-kyun), a budding actor, and Soo-jin (Jung Yu-mi), an office worker in the last month of her pregnancy.

Their everyday life in an old apartment is disrupted when Hyun-su begins speaking in his sleep, saying "Someone's inside."

Since then, Hyun-su sleepwalks at night but can't remember what happened the night before.

Soo-jin is frightened by her husband's eccentric behavior: scratching his skin until blood is drawn, swallowing raw meat from a refrigerator and even attempting to jump from the apartment as if possessed.

Hyun-su soon loses his role in a drama due to a scar on his face and receives treatment at a clinic, but his symptoms only intensify.

In the second part, the family treads a perilous tightrope as Soo-jin is now with a newborn baby in the house.

Overwhelmed with anxiety that Hyun-su may hurt himself or their daughter, Soo-jin can barely sleep and her mother calls a shaman to their house.

The shaman's diagnosis is ominous. Soo-jin is living with two men in the house: Hyun-su and a mysterious male soul who only wants to live with her, without the sound of a dog barking or a baby crying.

Soo-jin at first doubts what the shaman says. But the more she feeds the idea, the stronger it gets.

Soo-jin tenaciously investigates the cause of his symptoms with a firm belief in the motto written on a wooden plaque hung in the living room: "Together, there is nothing we can't overcome," and it unnerves Hyun-su.

Due to a combination of accumulated stress, sleep deprivation and postpartum emotional fluctuations, she shows paranoia and acts aggressively to protect her daughter.

The third part begins with Hyun-su's doctor telling him that his sleep disorder is finally cured. Soo-jin returns from a psychiatric hospital after weeks of treatment.

The couple is reunited in their house and has an argument over what has to be done to restore peace to the family, heading toward a gripping ending.

Mostly set in an old apartment, which causes inter-floor noise complaints, the newly wed's cozy home increasingly turns into a place of horror filled with potential hazards.

While the underlying emotion between the couple is love, the firm belief in the marital bond and parental commitment results in an unexpected outcome.

Its ending leaves more questions than answers: What keeps a couple in a marriage? How do supernatural beliefs evolve in one's life?

Formerly an assistant to Bong Joon-ho, director of the Oscar-winning film "Parasite," director Yu presents a unique horror story inspired by Korean contemporary culture of apartment living and shamanism, which practices healing rituals focused on spiritual causes of sickness.

Lee and Jung, who co-starred in Hong Sang Soo's three films -- "Lost in the Mountains" (2009), "Oki's Movie" (2010) and "Our Sunhee" (2013) -- vividly portray the couple's changing dynamics in a movie that blends witty black comedy elements.

"Sleep" was screened at Cannes Critics' Week section at the 2023 Cannes Film Festival, which focuses on the first and second films by emerging directors. It will hit local screens Sept. 6.

Source: Yonhap News Agency